Conjugated materials constitute a family of organic materials formed from coordinated compounds, polymers, copolymers and polymer mixtures which are characterised by the existence of functional groups with electron orbitals delocalised on different carbon atoms or other atoms, fundamentally nitrogen, oxygen or sulphur. These materials display optical and electronic properties similar to those observed in silicon or III-V semiconductors and are generically referred to as organic semiconductors. The spatial distribution of the charge density of the pi orbitals is highly anisotropic and as a consequence their optical and electronic properties depend on the orientation and on the molecular groupings.
Plastic electronics is a new sustainable type technology based on the use of thin films of conjugated compounds whose thicknesses vary between 1 and 100 nm. The products of plastic electronics are complementary to those of microelectronics since they are concentrated in low cost applications and they can take recycling or their waste has a very low environmental impact. As examples, mention can be made of the manufacture of labels, cards and intelligent clothing or electronic Identity cards. Conjugated compounds are easy to process and compatible with microelectronic processes. Nevertheless, it is crucial to control the molecular orientation, the order and the anisotropy of the molecular domains in order to obtain efficient devices.
The improvement in the electronic properties of a device formed from electronic molecules requires an understanding and control of the interactions between the organic molecules and the biological material. This is a complex problem since in an integrated circuit type device there coexist regions of differing properties, both chemical and electrical or topographical. All this means that the molecules undergo different interactions. This heterogeneity has an influence on the nucleation and growth processes, which in the end will determine the structure and morphology of the film. A self-organised growth would be very desirable since it would permit the active elements to be connected to the electrodes which would lead to a growth in the integration of the devices. All this makes it necessary to develop new procedures for promoting the spontaneous organisation of organic molecules.
Cited below are some patents and applications for obtaining nanostructures of organic materials.
1. Kano et al., Alps Electric Co. Ltd. (JP) Appl. No. 170715 Oct. 13, 1998;
2. Cox et al., Borealis Technical Limited (London UK), Appl. No. 045299 Mar. 20, 1998;
3. Biebuyck and Michel, International Business Machine Corporation (Armonk N.Y.), Appl. No. 690956 Aug. 1, 1996;
4. Calveley (Private Bag, MBE N180 Auckland, NZ) Appl. No. 474420, Dec. 29, 1999;
5. Chou S. and Zhuang L. (Princeton University NJ), Appl. No. WO 00/21689, April, 2000.
6. M. Murgia, P. Mei, F. Biscarini, C. Taliani (CNR-ISM Bologna, Italy) Italian Appl. No. MI 2000 A002075 Oct. 8 2001, extension PCT/EP02/11218 on October 7.
7. Katz H. E. (Agere Systems Guardian Corp. Orlando, Fla.), U.S. Pat. No. 6,403,397, Jun. 11, 2002.
8. Bulovic V. and Forrest S. R. (The Trustees of Princeton University, Princeton N.J.) U.S. Pat. No. 6,458,426, Oct. 1, 2002.
9. Cavallini M. and Biscarini F. (CNR-ISMN Sez. Bologna, Italy) Italian Appl. MI2002A001961, Sep. 16, 2002.
A sign of the impact of nanotechnology on the economic growth of developed economies can be seen from the level of government investment in Europe, USA and Japan. For example, in the sixth framework programme of the EU, nanotechnology is a priority area with financing of more than 1300 M.